Non-metallic flat ring gasket 8" Class 150 — ASME B16.21
Non-metallic flat ring gasket 8" Class 150 to ASME B16.21: gasket id 218.9 mm, gasket od 279.4 mm.
Dimensions of Non-metallic flat ring gasket 8" Class 150
| Symbol | Dimension | Value |
|---|---|---|
| · | Gasket ID | 218.9 mm (8.618 in) |
| · | Gasket OD | 279.4 mm (11.000 in) |
SKU TSH-GASKET-ASME-B16-21-CLASS-150-8 · Standard ASME B16.21 · verified by 2+ sources
Purchase description
NON-METALLIC FLAT RING GASKET, 8", CLASS 150, SS316 + GRAPHITE, CS RINGS, ASME B16.21
Available materials: SS316 + graphite, CS rings, SS316 + PTFE, CNAF (non-asbestos), Neoprene / EPDM rubber, Soft iron / SS316 (ring joint).
Notes
- Values from flangeboltchart.com (ASME B16.21-2021 Tables 4.1-4/4.1-5, inches) converted to mm at 25.4.
- Cross-checked: J.A. Harrison mm tables (e.g. NPS 1/2 ID 21.4, OD 47.6 / 54.0 mm) and Piping-World/Wermac rounded-mm tables (e.g. NPS 6: 168/222/251; NPS 12: 324/410/422; NPS 24: 610/718/775) agree after rounding.
- Wermac OD tolerance: +0/−1.5 mm NPS 12 and smaller, +0/−3.0 mm NPS 14 and larger.
- For RF flanges to ASME B16.5. NPS 22 not listed in sources.
Same size, other ratings
Other sizes — Non-metallic flat ring gasket, Class 150
Frequently asked questions
What are the main types of pipe flanges?
Weld neck (WN), slip-on (SO), blind (BL), socket weld (SW), threaded (THD), lap joint (LJ) and plate flanges. Special types include orifice, long weld neck, reducing flanges and spectacle blinds.
When should I use a weld neck flange instead of a slip-on?
Use weld neck flanges for high pressure, high or cycling temperature, and lines with vibration or fatigue loading. The tapered hub and full-penetration butt weld spread stress smoothly. Slip-on flanges are cheaper and easier to align, but their fatigue life is roughly one third of a WN.
What does Class 150, 300 or 600 mean on a flange?
The ASME class is a pressure-rating designation, not a pressure in psi. The allowable pressure depends on the material group and temperature. A Class 150 A105 flange is rated 19.6 bar at 38 °C but 13.8 bar at 200 °C.
Is a 150# flange rated for 150 psi?
No. A Class 150 carbon-steel flange is rated about 285 psi (19.6 bar) at ambient temperature, and about 170 psi (11.7 bar) at 260 °C. The "150" is a class number.